TAR/ARK Errors

Errors from ARK
Loading the archive /.../backups/DBs/TARs/accounts.18-08-14.tar.gz failed with the following error: Could not open the archive /.../backups/DBs/TARs/accounts.18-08-14.tar.gz, libarchive cannot handle it.

Errors from tar -xzvf
tar: This does not look like a tar archive
tar: Skipping to next header
tar: Exiting with failure status due to previous errors